Learn how some Go-specific language features help to simplify building web scrapers along with common pitfalls and best practices regarding web scraping.

Key Features

• Use Go libraries like Goquery and Colly to scrape the web

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• Common pitfalls and best practices to effectively scrape and crawl

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• Learn how to scrape using the Go concurrency model

Book Description

Web scraping is the process of extracting information from the web using various tools that perform scraping and crawling. Go is emerging as the language of choice for scraping using a variety of libraries. This book will quickly explain to you, how to scrape data data from various websites using Go libraries such as Colly and Goquery.

The book starts with an introduction to the use cases of building a web scraper and the main features of the Go programming language, along with setting up a Go environment. It then moves on to HTTP requests and responses and talks about how Go handles them. You will also learn about a number of basic web scraping etiquettes.

You will be taught how to navigate through a website, using a breadth-first and then a depth-first search, as well as find and follow links. You will get to know about the ways to track history in order to avoid loops and to protect your web scraper using proxies.

Finally the book will cover the Go concurrency model, and how to run scrapers in parallel, along with large-scale distributed web scraping.

What you will learn

• Implement Cache-Control to avoid unnecessary network calls

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• Coordinate concurrent scrapers

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• Design a custom, larger-scale scraping system

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• Scrape basic HTML pages with Colly and JavaScript pages with chromedp

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• Discover how to search using the "strings" and "regexp" packages

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• Set up a Go development environment

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• Retrieve information from an HTML document

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• Protect your web scraper from being blocked by using proxies

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• Control web browsers to scrape JavaScript sites

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Who this book is for

Data scientists, and web developers with a basic knowledge of Golang wanting to collect web data and analyze them for effective reporting and visualization.

© 2019 Packt Publishing (Ebook): 9781789612943

Data di uscita

Ebook: 30 gennaio 2019